A Wellhead Protection Area (WPA) is a type of designation made by the United States Environmental Protection Agency (EPA) to safeguard underground sources of drinking water, such as aquifers, from potential contamination. The purpose of designating a WPA is to prevent or limit the migration of pollutants from the surface into the aquifers which supply potable water wells. The EPA encourages states and municipalities to implement Wellhead Protection Programs to ensure the protection of underground sources of drinking water. The programs are usually carried out by state and local government agencies, and they involve a variety of variables such as zoning, land use planning, and other regulations designed to mitigate potential contamination to the WPA.
How Are Wellhead Protection Areas Determined?
WPAs are determined by mapping the area and features around a well or well field which contribute to the drinking water supply. Utilizing geologic and hydrologic principles, the WPA can be determined by the well’s/well field’s ability to pump water, as well as the water quality of the source aquifer. While states are allowed to implement their own programs for determining a WPA, the EPA must approve the program before it goes into effect. The EPA requires state’s proposals to include plans of action in case of contamination, regular testing of the source water, constant monitoring of groundwater elevations, and management of potential point source polluters which may contaminate the WPA.
The area and features which comprise the WPA include all groundwater recharge sources, such as streams, rivers, lakes, wetlands, and the process of the water cycle. Other groundwater recharge sources may include groundwater injection wells, storm water runoff, and other anthropogenic processes. Additionally, all potential point source polluters are included within the WPA, so that the state specific program can track, manage, and mitigate pollution which may originate from these sources.
How Are Wellhead Protection Areas Evaluated?
For these Wellhead Protection Areas it is critical to identify any potential sources of contamination which may impact groundwater conditions. Factories, gas stations, dry cleaning facilities, illegal landfills, and smelting facilities are just a few of the many types of point source polluters which may impact groundwater recharge features. Once contamination has entered into groundwater recharge features, contamination has the potential to leach directly into an aquifer. Once this leaching has occurred, the aquifer which is tapped for potable water may become contaminated.
The geology of an area plays an integral role in the ability for aquifers to become contaminated. Aquifers without containing layers, such as clays or silts, which bound the water bearing unit are readily contaminated through the leaching process. While a population center may be provided potable water from a contained aquifer, the threat is not fully mitigated. Chlorinated solvents, such as those utilized in dry cleaning facilities, readily migrate through dense clays and silts which may then leach into the aquifer.
To aid our clients in the undertaking of evaluating a Wellhead Protection Area for point source polluters, A3 Environmental Consultants identifies Federal, State, and County regulatory database listings within the Wellhead Protection Area. No matter the shape or size of the Wellhead Protection Area, A3E is able to identify any and all potential point source polluters within the designated area. A3E will then generate a report which tabulates all point source polluters, their locations, and the concerns associated with them. Additionally, figures are generated which display each point source polluter within the WPA. Further steps to evaluate a Wellhead Protection Area are available upon request through the review of historical documents such as fire insurance maps or aerial photographs. Review of these historical documents may reveal point source polluters which existed before Federal, State, and County regulatory oversight.
Tools For Wellhead Protection Areas
The EPA has deployed several tools for the public such as the Source Water Assessments and Source Water Protection tools. These tools provide information on WPAs, including maps and data on the quality of drinking water sources. The website allows users to search for information on specific wells and WPAs, which can be helpful in guiding a WPA Evolution.
Other tools which are utilized for determining a WPA include the Source Water Assessment Program (SWAP) and Mapping Tool. The 1996 amendment to the Federal Safe Drinking Water Act (SDWA) requires states to develop and implement a SWAP to protect critical sources of the public water supply, such as WPAs. The purpose of a SWAP is to identify areas which supply drinking water to the public and identify all potential point source polluters which may impact the drinking water.
Utilizing the geologic, hydrologic, and environmental practices described above A3E, is able to assist you in evaluating a WPA for potential point source polluters.